189 research outputs found

    Public Procurement and Associated Relevant Elements for a Habitable Public Domain

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    Public procurement remains a critical component of government undertakings because of the avenue it provides to acquire relevant resources to address various concerns of various segments of the population in various governance arrangements. The centrality of public procurement to governance is evidenced by enormous financial resources committed by developed and developing countries annually to meet various needs and expectations of the population. As a professional field, public procurement is defined by some associated elements and various scholars have examined such elements from systems’ perspective among others. One additional element which is worthy of attention and hereby the focus of this paper is professional procurement competency elements. This study uses dataset from the Universal Public Procurement Certification Council [UPPCC] survey to examine the likely determinant elements of public procurement based on multivariate analysis, specifically, exploratory factor analysis using Varimax with Kaiser normalization, and multiple linear regression. The analysis attests to multidimensionality of public procurement with strategic procurement planning; contract administration; procurement administration; supply management; sourcing; and negotiation process as key determinant elements. These key determinant elements converge into three clusters and further convey very critical, important, and necessary expectations for public procurement regardless of the locale. The study highlights the multifaceted and interwoven nature of public procurement and draws implications for theory, praxis and policy. Keywords: public procurement, purchasing, acquisition, professional procurement, procurement competency elements, contract management

    Charting a New Course: Professional Development Strategies for Improving Literacy Education Across the Curriculum

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    This paper reviews the effects of a program of professional development for literacy teachers in an urban, southeastern elementary school. During academic year 2002-2003, only 67% of fourth grade students met or exceeded state standards for achievement in reading as measured by the Criterion Referenced Competency Test (CRCT), and only 77% of fourth grade students met or exceeded state standards for achievement in English/language arts as measured by the CRCT (Georgia Department of Education, 2005)

    Spurious and functional correlates of the isotopic composition of a generalist across a tropical rainforest landscape

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    <p>Abstract</p> <p>Background</p> <p>The isotopic composition of generalist consumers may be expected to vary in space as a consequence of spatial heterogeneity in isotope ratios, the abundance of resources, and competition. We aim to account for the spatial variation in the carbon and nitrogen isotopic composition of a generalized predatory species across a 500 ha. tropical rain forest landscape. We test competing models to account for relative influence of resources and competitors to the carbon and nitrogen isotopic enrichment of gypsy ants (<it>Aphaenogaster araneoides</it>), taking into account site-specific differences in baseline isotope ratios.</p> <p>Results</p> <p>We found that 75% of the variance in the fraction of <sup>15</sup>N in the tissue of <it>A. araneoides </it>was accounted by one environmental parameter, the concentration of soil phosphorus. After taking into account landscape-scale variation in baseline resources, the most parsimonious model indicated that colony growth and leaf litter biomass accounted for nearly all of the variance in the Ξ΄<sup>15</sup>N discrimination factor, whereas the Ξ΄<sup>13</sup>C discrimination factor was most parsimoniously associated with colony size and the rate of leaf litter decomposition. There was no indication that competitor density or diversity accounted for spatial differences in the isotopic composition of gypsy ants.</p> <p>Conclusion</p> <p>Across a 500 ha. landscape, soil phosphorus accounted for spatial variation in baseline nitrogen isotope ratios. The Ξ΄<sup>15</sup>N discrimination factor of a higher order consumer in this food web was structured by bottom-up influences - the quantity and decomposition rate of leaf litter. Stable isotope studies on the trophic biology of consumers may benefit from explicit spatial design to account for edaphic properties that alter the baseline at fine spatial grains.</p

    Cellular expression, trafficking, and function of two isoforms of human ULBP5/RAET1G

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    Background: The activating immunoreceptor NKG2D is expressed on Natural Killer (NK) cells and subsets of T cells. NKG2D contributes to anti-tumour and anti-viral immune responses in vitro and in vivo. The ligands for NKG2D in humans are diverse proteins of the MIC and ULBP/RAET families that are upregulated on the surface of virally infected cells and tumours. Two splicing variants of ULBP5/RAET1G have been cloned previously, but not extensively characterised. Methodology/Principal Findings: We pursue a number of approaches to characterise the expression, trafficking, and function of the two isoforms of ULBP5/RAET1G. We show that both transcripts are frequently expressed in cell lines derived from epithelial cancers, and in primary breast cancers. The full-length transcript, RAET1G1, is predicted to encode a molecule with transmembrane and cytoplasmic domains that are unique amongst NKG2D ligands. Using specific anti-RAET1G1 antiserum to stain tissue microarrays we show that RAET1G1 expression is highly restricted in normal tissues. RAET1G1 was expressed at a low level in normal gastrointestinal epithelial cells in a similar pattern to MICA. Both RAET1G1 and MICA showed increased expression in the gut of patients with celiac disease. In contrast to healthy tissues the RAET1G1 antiserum stained a wide variety or different primary tumour sections. Both endogenously expressed and transfected RAET1G1 was mainly found inside the cell, with a minority of the protein reaching the cell surface. Conversely the truncated splicing variant of RAET1G2 was shown to encode a soluble molecule that could be secreted from cells. Secreted RAET1G2 was shown to downregulate NKG2D receptor expression on NK cells and hence may represent a novel tumour immune evasion strategy. Conclusions/Significance: We demonstrate that the expression patterns of ULBP5RAET1G are very similar to the well-characterised NKG2D ligand, MICA. However the two isoforms of ULBP5/RAET1G have very different cellular localisations that are likely to reflect unique functionality

    Life-threatening hypersplenism due to idiopathic portal hypertension in early childhood: case report and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Idiopathic portal hypertension (IPH) is a disorder of unknown etiology and is characterized clinically by portal hypertension, splenomegaly, and hypersplenism accompanied by pancytopenia. This study evaluates the pathogenic concept of the disease by a systematic review of the literature and illustrates novel pathologic and laboratory findings.</p> <p>Case Presentation</p> <p>We report the first case of uncontrolled splenic hyperperfusion and enlargement with subsequent hypersplenism leading to life-threatening complications of IPH in infancy and emergent splenectomy.</p> <p>Conclusions</p> <p>Our results suggest that splenic NO and VCAM-1, rather than ET-1, have a significant impact on the development of IPH, even at a very early stage of disease. The success of surgical interventions targeting the splenic hyperperfusion suggests that the primary defect in the regulation of splenic blood flow seems to be crucial for the development of IPH. Thus, beside other treatment options splenectomy needs to be considered as a prime therapeutic option for IPH.</p

    Mutations in a member of the ADAMTS gene family cause thrombotic thrombocytopenic purpura

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    Thrombotic thrombocytopenic purpura (TTP) is a life-threatening systemic illness of abrupt onset and unknown cause. Proteolysis of the blood-clotting protein von Willebrand factor (VWF) observed in normal plasma is decreased in TTP patients. However, the identity of the responsible protease and its role in the pathophysiology of TTP remain unknown. We performed genome-wide linkage analysis in four pedigrees of humans with congenital TTP and mapped the responsible genetic locus to chromosome 9q34. A predicted gene in the identifed interval corresponds to a segment of a much larger transcript, identifying a new member of the ADAMTS family of zinc metalloproteinase genes (ADAMTS13). Analysis of patients' genomic DNA identified 12 mutations in the ADAMTS13 gene, accounting for 14 of the 15 disease alleles studied. We show that deficiency of ADAMTS13 is the molecular mechanism responsible for TTP, and suggest that physiologic proteolysis of VWF and/or other ADAMTS13 substrates is required for normal vascular homeostasis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62592/1/413488a0.pd

    Control of triceps surae stimulation based on shank orientation using a uniaxial gyroscope during gait

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    This article presents a stimulation control method using a uniaxial gyroscope measuring angular velocity of the shank in the sagittal plane, to control functional electrical stimulation of the triceps surae to improve push-off of stroke subjects during gait. The algorithm is triggered during each swing phase of gait when the angular velocity of the shank is relatively high. Subsequently, the start of the stance phase is detected by a change of sign of the gyroscope signal at approximately the same time as heel strike. Stimulation is triggered when the shank angle reaches a preset value since the beginning of stance. The change of angle is determined by integrating angular velocity from the moment of change of sign. The results show that the real-time reliability of stimulation control was at least 95% for four of the five stroke subjects tested, two of which were 100% reliable. For the remaining subject, the reliability was increased from 50% found during the experiment, to 99% during offline processing. Our conclusion is that a uniaxial gyroscope on the shank is a simple, more reliable alternative to the heel switch for the purpose of restoring push-off of stroke subjects during gait

    Remodelling of Cortical Actin Where Lytic Granules Dock at Natural Killer Cell Immune Synapses Revealed by Super-Resolution Microscopy

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    Super-resolution 3D imaging reveals remodeling of the cortical actin meshwork at the natural killer cell immune synapse, which is likely to be important for secretion of lytic granules

    NK Cell Terminal Differentiation: Correlated Stepwise Decrease of NKG2A and Acquisition of KIRs

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    BACKGROUND: Terminal differentiation of NK cells is crucial in maintaining broad responsiveness to pathogens and discriminating normal cells from cells in distress. Although it is well established that KIRs, in conjunction with NKG2A, play a major role in the NK cell education that determines whether cells will end up competent or hyporesponsive, the events underlying the differentiation are still debated. METHODOLOGY/PRINCIPAL FINDINGS: A combination of complementary approaches to assess the kinetics of the appearance of each subset during development allowed us to obtain new insights into these terminal stages of differentiation, characterising their gene expression profiles at a pan-genomic level, their distinct surface receptor patterns and their prototypic effector functions. The present study supports the hypothesis that CD56dim cells derive from the CD56bright subset and suggests that NK cell responsiveness is determined by persistent inhibitory signals received during their education. We report here the inverse correlation of NKG2A expression with KIR expression and explore whether this correlation bestows functional competence on NK cells. We show that CD56dimNKG2A-KIR+ cells display the most differentiated phenotype associated to their unique ability to respond against HLA-E+ target cells. Importantly, after IL-12+IL-18 stimulation, reacquisition of NKG2A strongly correlates with IFN-gamma production in CD56dimNKG2A- NK cells. CONCLUSIONS/SIGNIFICANCE: Together, these findings call for the reclassification of mature human NK cells into distinct subsets and support a new model, in which the NK cell differentiation and functional fate are based on a stepwise decrease of NKG2A and acquisition of KIRs
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